Love it or hate it, fat plays an important role in the body. So if 2015 is the year you plan to take control of your body fat, start off by learning a little more about it.
Body fat, also known as adipose tissue, is a type of loose connective tissue – sort of like the packing material of the body. Loose connective tissue fills the spaces between organs and forms a layer that separates the skin from deeper structures. What distinguishes body fat from other loose connective tissue is its high concentration of adipocytes or lipocytes (you guessed it – fat cells).
Fat cells are cells which are specialised to store energy as fat. The main role of your body fat is to store energy. Body fat also plays an important role in padding and cushioning the body from shocks. It also protects us from slow heat loss through the skin, and plays a role in tissue regeneration. Research has found that fat cells play an important role in our hormonal system. Researchers believe that having too much or too little body fat may affect your fertility, hunger levels, immune function, and insulin resistance.
The average adult has about 30 billion fat cells, which make up about 13.5kg of their body weight. Fat cells are metabolically active, continually breaking down and replacing the lipids within their cells. In times of scarcity, such as on a weight loss diet, they shrink but do not decrease in number. In times of plenty, fat cells can stretch about fourfold to store more lipids without increasing in number. However if circulating lipid levels remain high, surrounding cells in the loose connective tissue can divide and differentiate to create more fat cells.
Though body fat levels and distribution change throughout life, staying within a healthy range affects our health and longevity. Carrying excess body fat is associated with several metabolic diseases, cancers, and age-related illnesses. Maintaining an optimal body fat level is also crucial for athletes, since excess body fat means excess body weight that needs to be carried and can limit flexibility. An optimum body fat level for elite sports performance may be outside regular healthy body fat recommendations.
A healthy level of body fat
To determine what is a healthy level of body fat it’s best to distinguish essential fat from storage fat. Essential fat is the fat stored in small amounts in your bone marrow, organs, central nervous system, and muscles. For men, essential fat should make up 3% of their bodyweight. Women need extra fat, so 12% of their bodyweight should be essential fat. Men and women need similar amounts of storage fat, the “expendable” fat, which includes the deep fat around internal organs, the fat under the skin, and the fat inside muscles. When you gain or lose fat it is the storage fat levels that are fluctuating. The table below demonstrates the recommended body fat percentage for different age groups.
Measuring your body fat percentage
It’s no secret to dieters and exercisers that weight isn’t an accurate measure of body fat. According to the scales you haven’t lost a pound, but your belt might be two notches tighter. The scales measure your total body weight including muscle, internal organs, fluid, bones, and connective tissue. When you first start exercising your muscle weight and blood volume often increase, so you can lose body fat in that first week yet your weight may go up. Increasing your muscle mass is a great way to help lose body fat, so don’t let those bathroom scales discourage you – find a better way to measure your progress.
There are a variety of ways to distinguish your body fat weight from your lean body weight. Some bathroom scales claim to measure body fat, but they aren’t known for their reliability. Full body scanning and underwater weighing are some of the most reliable methods, but they aren’t a practical option for most people.
A skinfold test by an experienced fitness assessor is the best option for most people to measure their progress at regular intervals. Since reliability for skinfold measurements depends on the person doing the testing, you’ll need to do it with an experienced personal trainer who can measure your body fat at regular intervals.